1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #include <stdio.h> 27 #include <ndbm.h> 28 #include <netdb.h> 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <netinet/in.h> 32 #include <arpa/inet.h> 33 #include <string.h> 34 #include <ctype.h> 35 #include <errno.h> 36 37 /* 38 * Filter to convert both IPv4 and IPv6 addresses from /etc/hosts file. 39 */ 40 41 /* 42 * Size of buffer for input lines. Add two bytes on input for newline 43 * and terminating NULL. Note that the practical limit for data 44 * storage in ndbm is (PBLKSIZ - 3 * sizeof (short)). Though this 45 * differs from spec 1170 the common industry implementation does 46 * conform to this slightly lower limit. 47 */ 48 49 #define OUTPUTSIZ (PBLKSIZ - 3 * sizeof (short)) 50 #define INPUTSIZ (OUTPUTSIZ + 2) 51 52 static int ipv4 = -1; 53 static char *cmd; 54 int warning = 0; 55 56 static void verify_and_output(const char *key, char *value, int lineno); 57 58 void 59 usage() 60 { 61 fprintf(stderr, "stdhosts [-w] [-n] [in-file]\n"); 62 fprintf(stderr, "\t-w\tprint malformed warning messages.\n"); 63 exit(1); 64 } 65 66 int 67 main(int argc, char **argv) 68 { 69 char line[INPUTSIZ]; 70 char adr[INPUTSIZ]; 71 char nadr[INET6_ADDRSTRLEN]; /* Contains normalised address */ 72 const char *nadrp; /* Pointer to the normalised address */ 73 char *trailer; 74 char *commentp; /* Pointer to comment character '#' */ 75 int c; 76 FILE *fp; 77 int lineno = 0; /* Input line counter */ 78 struct in_addr in; /* Used for normalising the IPv4 address */ 79 struct in6_addr in6; /* Used for normalising the IPv6 address */ 80 char *fgetsp; /* Holds return value for fgets() calls */ 81 int endoffile = 0; /* Set when end of file reached */ 82 83 if (cmd = strrchr(argv[0], '/')) 84 ++cmd; 85 else 86 cmd = argv[0]; 87 88 while ((c = getopt(argc, argv, "v:wn")) != -1) { 89 switch (c) { 90 case 'w': /* Send warning messages to stderr */ 91 warning = 1; 92 break; 93 case 'n': 94 ipv4 = 0; 95 break; 96 default: 97 usage(); 98 exit(1); 99 } 100 } 101 102 if (optind < argc) { 103 fp = fopen(argv[optind], "r"); 104 if (fp == NULL) { 105 fprintf(stderr, "%s: can't open %s\n", 106 cmd, argv[optind]); 107 exit(1); 108 } 109 } else 110 fp = stdin; 111 112 while (!endoffile && 113 (fgetsp = fgets(line, sizeof (line), fp)) != NULL) { 114 lineno++; 115 116 /* Check for comments */ 117 if ((commentp = strchr(line, '#')) != NULL) { 118 if ((line[strlen(line) - 1] != '\n') && 119 (strlen(line) >= (sizeof (line) - 1))) { 120 /* 121 * Discard the remainder of the line 122 * until the newline or EOF, then 123 * continue to parse the line. Use 124 * adr[] rather then line[] to 125 * preserve the contents of line[]. 126 */ 127 while ((fgetsp = fgets(adr, sizeof (adr), 128 fp)) != NULL) { 129 if (adr[strlen(adr) - 1] == '\n') 130 break; 131 } 132 if (fgetsp == NULL) 133 endoffile = 1; 134 } 135 /* Terminate line[] at the comment character */ 136 *commentp = '\0'; 137 } else if ((line[strlen(line) - 1] != '\n') && 138 (strlen(line) >= (sizeof (line) - 1))) { 139 /* 140 * Catch long lines but not if this is a short 141 * line with no '\n' at the end of the input. 142 */ 143 if (warning) 144 fprintf(stderr, 145 "%s: Warning: more than %d " 146 "bytes on line %d, ignored\n", 147 cmd, sizeof (line) - 2, lineno); 148 /* 149 * Discard the remaining lines until the 150 * newline or EOF. 151 */ 152 while ((fgetsp = fgets(line, sizeof (line), 153 fp)) != NULL) 154 if (line[strlen(line) - 1] == '\n') 155 break; 156 if (fgetsp == NULL) 157 endoffile = 1; 158 continue; 159 } 160 161 if (sscanf(line, "%s", adr) != 1) { /* Blank line, ignore */ 162 continue; 163 } 164 165 if ((trailer = strpbrk(line, " \t")) == NULL) { 166 if (warning) 167 fprintf(stderr, 168 "%s: Warning: no host names on line %d, " 169 "ignored\n", cmd, lineno); 170 continue; 171 } 172 173 /* 174 * check for valid addresses 175 * 176 * Attempt an ipv4 conversion, this accepts all valid 177 * ipv4 addresses including: 178 * d 179 * d.d 180 * d.d.d 181 * Unfortunately inet_pton() doesn't recognise these. 182 */ 183 184 in.s_addr = inet_addr(adr); 185 if (-1 != (int)in.s_addr) { 186 /* 187 * It's safe not to check return of NULL as 188 * nadrp is checked for validity later. 189 */ 190 nadrp = inet_ntop(AF_INET, &in, nadr, sizeof (nadr)); 191 } else { 192 nadrp = NULL; /* Not a valid IPv4 address */ 193 } 194 195 if (nadrp == NULL) { 196 if (inet_pton(AF_INET6, adr, &in6) == 1) { 197 nadrp = inet_ntop(AF_INET6, &in6, 198 nadr, sizeof (nadr)); 199 } 200 if (nadrp == NULL) { /* Invalid IPv6 too */ 201 if (warning) 202 fprintf(stderr, 203 "%s: Warning: malformed" 204 " address on" 205 " line %d, ignored\n", 206 cmd, lineno); 207 continue; 208 } else if (ipv4) { 209 continue; /* Ignore valid IPv6 */ 210 } 211 } 212 213 verify_and_output(nadrp, trailer, lineno); 214 215 } /* while */ 216 return (0); 217 /* NOTREACHED */ 218 } 219 220 /* 221 * verify_and_output 222 * 223 * Builds and verifies the output key and value string 224 * 225 * It makes sure these rules are followed: 226 * key + separator + value <= OUTPUTSIZ (for ndbm) 227 * names <= MAXALIASES + 1, ie one canonical name + MAXALIASES aliases 228 * It will also ignore everything after a '#' comment character 229 */ 230 static void 231 verify_and_output(const char *key, char *value, int lineno) 232 { 233 char *p; /* General char pointer */ 234 char *endp; /* Points to the NULL at the end */ 235 char *namep; /* First character of a name */ 236 char tmpbuf[OUTPUTSIZ+1]; /* Buffer before writing out */ 237 char *tmpbufp = tmpbuf; /* Current point in output string */ 238 int n = 0; /* Length of output */ 239 int names = 0; /* Number of names found */ 240 int namelen; /* Length of the name */ 241 242 if (key) { /* Just in case key is NULL */ 243 n = strlen(key); 244 if (n > OUTPUTSIZ) { 245 if (warning) 246 fprintf(stderr, 247 "%s: address too long on " 248 "line %d, line discarded\n", 249 cmd, lineno); 250 return; 251 } 252 memcpy(tmpbufp, key, n+1); /* Plus the '\0' */ 253 tmpbufp += n; 254 } 255 256 if (value) { /* Just in case value is NULL */ 257 p = value; 258 if ((endp = strchr(value, '#')) == 0) /* Ignore # comments */ 259 endp = p + strlen(p); /* Or endp = EOL */ 260 do { 261 /* 262 * Skip white space. Type conversion is 263 * necessary to avoid unfortunate effects of 264 * 8-bit characters appearing negative. 265 */ 266 while ((p < endp) && isspace((unsigned char)*p)) 267 p++; 268 269 if (p == endp) /* End of the string */ 270 break; 271 272 names++; 273 if (names > (MAXALIASES+1)) { /* cname + MAXALIASES */ 274 if (warning) 275 fprintf(stderr, 276 "%s: Warning: too many " 277 "host names on line %d, " 278 "truncating\n", 279 cmd, lineno); 280 break; 281 } 282 283 namep = p; 284 while ((p < endp) && !isspace((unsigned char)*p)) 285 p++; 286 287 namelen = p - namep; 288 n += namelen + 1; /* single white space + name */ 289 *p = '\0'; /* Terminate the name string */ 290 if (n > OUTPUTSIZ) { 291 if (warning) 292 fprintf(stderr, 293 "%s: Warning: %d byte ndbm limit " 294 "reached on line %d, truncating\n", 295 cmd, OUTPUTSIZ, lineno); 296 break; 297 } 298 299 if (names == 1) /* First space is a '\t' */ 300 *tmpbufp++ = '\t'; 301 else 302 *tmpbufp++ = ' '; 303 304 memcpy(tmpbufp, namep, namelen+1); /* Plus the '\0' */ 305 tmpbufp += namelen; 306 307 if (p < endp) 308 p++; /* Skip the added NULL */ 309 310 } while (p < endp); 311 } 312 313 if (names > 0) { 314 fputs(tmpbuf, stdout); 315 fputc('\n', stdout); 316 } else { 317 if (warning) 318 fprintf(stderr, 319 "%s: Warning: no host names on line %d, " 320 "ignored\n", cmd, lineno); 321 } 322 } 323